Commonly owned U.S. patent application Ser. No. 09/819,998, filed Mar. 29, 2001, filed concurrently herewith, for Compact Apparatus and System for Creating and Dispensing Cushioning Dunnage, is hereby incorporated by reference.
The invention relates to an apparatus for enabling a material to be unwound from a roll of the material by pulling the material from the roll while maintaining tension on the material when pulling suddenly stops. An implementation is an automatic roll tensioner for a material dispensing system in an apparatus for converting sheets of paper into void fill and cushioning dunnage.
It is known to dispense material such as paper or plastic from a roll of the material by pulling the material to unwind it from the roll. Equipment can be used to unwind the material from the roll or unwinding can be accomplished manually by pulling on the material. As an example, paper which is used to form packaging dunnage is supplied on rolls mounted to a supply end of a dunnage conversion machine. The rolls are generally rotatably supported on a mounting apparatus to facilitate paper supply to the conversion machine. U.S. Pat. No. 5,749,539 discloses a relatively complex mandrel assembly for mounting a roll of paper onto a mounting frame. A two-piece spindle extends through the length of the paper, extending beyond the mounting apparatus. An end of one spindle piece must be inserted through one end of the paper roll and into an opening in an end of a second spindle piece, which must be inserted into a second end of the paper roll to form the spindle. Plugs which are rotatably mounted near each end of the spindle support either end of the paper roll on the spindle. The plugs are retained on the spindle by a plurality of pins that must be inserted diametrically through the spindle to form abutments at opposite axial ends of the plugs. The spindle is then fixed to the mounting frame by additional pins which must be inserted through the spindle into the mounting frame, preventing the spindle from rotating relative to the mounting frame.
As the paper is drawn from the roll, the plugs rotate with the roll and the plugs rotate freely about the fixed spindle. This prior art mandrel assembly does not provide the ability to apply tension to the paper roll except for whatever rotational friction is generated between the spindle and the plugs. In the absence of tension, paper backlash may occur when the drive motor is stopped to cut the paper. Excess backlash can separate the paper from the forming mechanism, reducing the forming and shaping capabilities of the machine, producing an unsatisfactory product. That is, the roll of material can keep turning even after the material has suddenly stopped being pulled forward which causes the material to lose tension and slacken, and extra material to hang loosely from the roll. Then, when the material is quickly pulled forward again, the slack is taken out before the roll begins turning, causing the material to rip. There is a need for an apparatus which can be integrated with any type of equipment that unwinds materials such as paper or plastic from a roll where constant material tension can be maintained and controlled.
The present invention addresses this need in providing an apparatus for enabling a material to be unwound from a roll of the material by pulling the material from the roll while maintaining tension on the material when pulling suddenly stops. In a disclosed, example embodiment, the apparatus comprises an arrangement for positioning a roll of material such that the roll can be rotated about a longitudinal axis of the roll by pulling the material from the roll to unwind material from the roll, and a mechanism actuated by the roll of material when the roll of material is positioned by the arrangement for applying frictional resistance to the rotation of the roll of material at a plurality of circumferentially spaced locations on the periphery of the roll of material.
The example embodiment is in the form of an automatic roll tensioner especially for use in an apparatus for converting sheets of paper into void fill and cushioning dunnage. In the apparatus, a supply assembly supports the roll of paper to be converted. A conversion assembly through which paper from the roll of material can be pulled folds and forms the paper into pillow-like shapes for use as cushioning dunnage. The automatic roll tensioner of the invention positions the roll of paper such that the roll can be rotated about a longitudinal axis of the roll by pulling the material from the roll to unwind material from the roll. A mechanism of the roll tensioner is actuated by the roll of material when the roll is positioned by the arrangement for applying frictional resistance to the rotation of the roll of material at a plurality of circumferentially spaced locations on the periphery of the roll as a function of the weight of the roll of material positioned by the arrangement. The roll tensioner automatically adjusts tension based on the weight of the roll. The material roll does not require a core or support such as a rod or mandrel.
These and other features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, one example embodiment in accordance with the present invention.